SI Units:-

1. length - meters

2. mass - kilometers

3. time - seconds

4. volume - cubic meters

5. area - meters squared

6. temperature - degrees celsius

density - 1kg per meter cubed

conservation of energy states: energy is neither created or destroyed but changes from one form to another

our main energy source is the SUN

forms of energy

• potential (elastic,gravitational,chemical)

• kinetic (all moving things contain)

• heat

• sound

• electrical

• light

potential energy

potential energy has 3 different types (elastic, gravitational,chemical). It is stored energy and it has to be released

chemical potential energy: energy stored i fuels, food and batteries.

kinetic energy

all moving things contain kinetic energy

the heavier an object is, the more kinetic energy it has.

heat energy

heat energy is split into three parts (conduction, convection and radiation)

conduction- is when two metal surfaces are in contact with each other. The heat is not then transferred by this contact.

convection- the flow of heat caused by the motion of a liquid or a gas.

radiation- energy that moves from one place to another (this is how the heat from the sun travels to the earth since radiation does not require particles)

to keep out heat and keep in the warmth are made from thatch bricks and cement

electrical energy

the national grid is a network of power lines that carry high voltages of electrical energy to towns, cities, etc

a car uses e/e for providing a spark in the battery to ignite the fuel and getting the fuels moving

sources of electrical energy include:- power stations(thermal,hydro,nuclear) and batteries (potential chemical).

alternate e/e sources:

• windmills-kinetic energy of the wind

• nuclear-heat energy from splitting atoms

• generators-chemical energy in petrol/diesel

  solar energy - contains both heat and light energy. panels trap light energy and create electrical energy using photo-voltaic cells. the energy is now stored in batteries and used to power appliances.

light energy

sources-

1. hot or burning objects

2. sun

3. smaller sources include; fires, light bulbs, gas lamps,candles,glow worms

light enables you to see things

does not require particles in order to move

light travels in straight lines

plants use light energy during photosynthesis to produce simple sugars(chemical potential energy)

photosynthesis = carbon dioxide + water + sunlight

sound energy

any object that vibrates produces sound

a vibration is a small but very fast backwards and forwards motion.

sound does not travel through a vacuum because it requires particles. this is why we don’t hear things exploding in space

sound travels faster in water than in air because water particles are more closer together than air particles (so there would be more vibrations of particles)

sound moves by the vibrations in the air causing your ear drums vibrate and these vibrations are interpreted by the brain.

wind instruments(flutes, trumpets,etc)-cause the column of air to vibrate

stringed instruments- strings are made to vibrate

percussions- you need to release kinetic energy onto the drum to make it vibrate.

The Human Voice

the larynx (voice box) is made up of thin membranes stretched across a space.

these membranes are called vocal chords

how does a thermal power station work?

• coal is heated to create heat energy to boil water

• steam is then forced into piped and is used to turn turbines

potential—heat—kinetic—electrical energy

how does a hydro-electrical power station?

• water is released for behind a dam wall

• running water turns turbines

• electrical energy is created and transported

biomass- energy from plants